What is a possible complication of untreated erythroblastosis fetalis?

• A. Heart failure
• B. Severe anemia in the fetus
• C. Oxygen toxicity
• D. Pulmonary hypertension

Answer: (B)

Untreated erythroblastosis fetalis can lead to severe anemia in the fetus as a direct result of the pathological process involved. Erythroblastosis fetalis occurs when there is an incompatibility between the blood types of the mother and fetus, often due to Rh factor incompatibility. The mother's immune system produces antibodies against the fetus's red blood cells, leading to hemolysis (destruction of red blood cells).

This hemolytic process significantly decreases the number of red blood cells available to carry oxygen throughout the fetus's body, which in turn results in anemia. Severe anemia can lead to a host of other complications, including fetal hydrops (an accumulation of fluid in the fetus), heart failure, and in extreme cases, stillbirth. Therefore, severe anemia is indeed a critical complication of untreated erythroblastosis fetalis and underscores the importance of timely diagnosis and management to prevent adverse outcomes for the fetus.